In U.S. Pat. No. 4,133,441 a unitary, molded injection site is shown residing upon the end of a flared tube, which may be an access tube for a flexible parenteral solution container, a blood bag, a solution or blood administration set, a blood set for a dialyzer or blood oxygenator, or the like. The injection site of the above-cited patent is molded in unitary manner, and is formed of self-sealing, piercable resilient material, comprising a central, needle-receiving portion, and a skirt portion carried by the central portion and extending in a direction away from the central portion.
To install the injection site of the cited patent on a tubular member, the needle-receiving portion is positioned on the tubular member, and then the generally cylindrical skirt portion is convoluted out of its original, unstressed configuration into a position which surrounds the outer end of the tubular portion.
Rings, positioned circumferentially about the skirt portion, are originally molded on the inside of the skirt or tubular portion, but in the stressed, installed position, they reside on the outside of the structure to serve as compression members to assist in holding the skirt portion in squeezing relation to the tube.
In accordance with this invention, a unitary, molded injection site for carrying upon a support tube is provided in which the tendency of the injection site to "pop off" of the tube end is significantly reduced. This is so because the injection site of this invention resides on the tube end in relatively unstressed configuration, so that there are only greatly reduced forces, if any, urging the "pop off" of the injection site when, for example, a needle is being withdrawn from the site after penetrating it.